A process for connecting two bodies forming parts of an electromechanical, fluid and optical microsystem, wherein a welding region is formed on a first body; an electrically conductive region and a spacing region are formed on a second body; the spacing region extends near the electrically conductive region and has a second height smaller than said first height. One of the first and second bodies is turned upside down on the other, and the two bodies are welded together by causing the electrically conductive region to melt so that it adheres to the welding region and collapses until its height becomes equal to that of the spacing region. Thereby it is possible to seal active parts or micromechanical structures with respect to the outside world, self-align the two bodies during bonding, obtain an electrical connection between the two bodies, and optically align two optical structures formed on the two bodies.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A device forming an electromechanical or optical microsystem, the device comprising: a first body and a second body welded together through a mechanical and electrical connection structure, the mechanical and electrical connection structure comprising: an electrically conductive region welded between said first body and said second body; and a unitary spacer arranged near said electrically conductive region and extending between the first and second bodies, the spacer having at least three sides defining a first cavity surrounding an active region or a plug of the electromechanical or optical microsystem.
2. The device according to claim 1 , wherein said electrically conductive region is of a low-melting eutectic material.
3. The device according to claim 2 , wherein said low-melting eutectic material is formed by alternating layers of gold and tin.
4. The device according to claim 1 , wherein said spacer is of dielectric material.
5. The device according to claim 4 , wherein said dielectric material is chosen from among a spun polymer, such as SU8, polyimide, a composite material formed by laminated polymer layers, such as a photosensitive stick foil, and oxynitrides.
6. The device according to claim 1 , wherein said spacer also forms a completely enclosed second cavity surrounding said electrically conductive region.
7. The device according to claim 1 , further comprising a metal region which extends on top of said second body and beneath said electrically conductive region.
8. The device according to claim 7 , wherein said welding region and said metal region are of a material chosen from among titanium, gold and nickel.
9. A device forming an electromechanical or optical microsystem, comprising: a first body of semiconductor material; a first metal region, formed on a first surface of the first body; a second body of semiconductor material spaced apart from the first body; a spacer separating the first and second body and in contact with the first surface of the first body and a first surface of the second body, the spacer having at least three sides defining a first cavity between the first and second bodies; a second metal region, formed on a first surface of the second body; and a connection structure bonded to the first and second metal regions, forming thereby an electrical connection between the first and second metal regions, the connection structure being surrounded by the first cavity.
10. The device of claim 9 wherein the connection structure is a low-melting eutectic material welded to the first and second metal regions.
11. The device of claim 9 wherein, the first and second metal regions and the connection structure are formed within the first cavity defined by the spacer.
12. The device of claim 9 wherein the spacer further defines a completely enclosed second cavity between the first and second bodies, the device further comprising a micromechanical structure formed within the second cavity defined by the spacer.
13. The device of claim 9 wherein the first body of semiconductor material is formed of quartz.
14. The device of claim 13 , further comprising a mirror formed on a second surface of the first body.
15. The device of claim 13 , further comprising a diffractive lens formed on the second surface of the first body.
16. The device of claim 1 , wherein the active region comprises a suspended electromechanical structure.
17. The device of claim 1 , wherein the active region comprises an optical structure.
18. The device of claim 17 , further comprising a mirror formed on a surface of the first body opposite the optical structure.
19. The device of claim 17 , further comprising: a third body welded to the first body adjacent to the second body; and an additional spacer formed between the first and third bodies and including a completely enclosed second cavity surrounding an additional active region of the microsystem.
20. The device of claim 19 , further comprising first and second mirrors formed on opposite faces of the first body.
21. The device of claim 1 wherein the first and second bodies are wafers of semiconductor material.
22. A device forming an electromechanical or optical microsystem, the device comprising: a first body; a second body spaced apart from the first body; an active region of the microsystem, the active region being positioned between the first and second bodies; and a single spacer extending between the first and second bodies and including a completely enclosed first cavity that surrounds the active region and that is defined by the spacer and the first and second bodies; and an electrically conductive region welded between the first and second bodies and positioned adjacent to the spacer.
23. The device of claim 22 , wherein said electrically conductive region is of a low-melting eutectic material.
24. The device of claim 23 , wherein said low-melting eutectic material is formed by alternating layers of gold and tin.
25. The device of claim 22 , wherein said spacer is of dielectric material.
26. The device of claim 25 , wherein said dielectric material is chosen from among a spun polymer, such as SU8, polyimide, a composite material formed by laminated polymer layers, such as a photosensitive stick foil, and oxynitrides.
27. The device of claim 22 wherein the active region comprises a suspended electromechanical structure.
28. The device of claim 22 , wherein the active region comprises an optical structure.
29. The device of claim 28 , further comprising a mirror formed on a surface of the first body opposite to the optical structure.
30. The device of claim 22 , further comprising: a third body welded to the first body and adjacent to the second body; and an additional spacer extending between the first and third bodies and including a completely enclosed second cavity that surrounds an additional active region of the microsystem.
31. The device of claim 22 wherein the first and second bodies are wafers of semiconductor material.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
January 29, 2002
May 12, 2009
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